Reduction of power consumption of an image processing apparatus represented by a composite machine or the like has become one of important problems due to increase in users' interest in energy saving. A user often determines a product that the user is going to purchase placing importance on whether or not power consumption described in a product catalogue is low.
Moreover, energy saving is also recommended in foreign countries and various regulations and standards are relaxed. For example, the Energy Saving Law has been enacted in Japan. In the foreign countries, there are standards such as Energy Star and Blue Angel, under which a product which clears fixed conditions is allowed to be affixed a logo or the like. In order to clear the conditions, there are a lot of ideas incorporated in every product, for example, introducing an operation mode such as a sleep mode, a standby mode, or a low power mode.
On the other hand, Japanese Patent Application Laid-Open No. 08-130595 discloses a facsimile apparatus for printing a history of executing energy saving together with an execution mode/time, and also discloses a mechanism in which, when a sleep condition is satisfied, the facsimile apparatus executes energy saving such as starting up a sub-CPU and stopping a main CPU, stores a total time of the energy saving, and displays reduced costs based on the stored time.
However, in the composite machine as described above, respective operations such as a copy output mode, a print output mode, a FAX transmission mode, and a FAX reception output mode are instructed to be executed at arbitrary timing. Thus, power consumption in such a composite machine cannot be monitored. For example, there was a problem in that it was necessary to monitor a history of power consumption even if the print output mode and the FAX transmission mode were executed in parallel.